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Digital Intervention Strategies for Increasing Physical Activity Among Preschoolers: Systematic Review.
Swindle, T, Poosala, AB, Zeng, N, Børsheim, E, Andres, A, Bellows, LL
Journal of medical Internet research. 2022;24(1):e28230
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Digital strategies to improve the diet and activity of pre-schoolers are increasing due to their accessibility and relatively low cost to set up. This systematic review of 8 studies aimed to determine the quality of the studies that have been performed to date, and to determine the effectiveness of the digital strategies used to increase physical activity. The results showed that the studies reviewed had a small sample size. Only 2 studies showed positive changes in physical activity of pre-schoolers and these approaches were child led, but the studies were low quality. Parent focused interventions did not improve the physical activity of pre-schoolers. It was concluded that digital child-centred activities may be of benefit to physical activity in pre-schoolers, however parent-focused digital interventions may be ineffective. This study could be used by healthcare professionals to understand the importance of using digital strategies which engage children to improve their health.
Abstract
BACKGROUND Digital interventions are increasingly used to improve health behaviors. Improved access and lower costs (relative to in-person interventions) make such interventions appealing. Specifically, digital platforms may be a promising approach for increasing physical activity (PA) in young children. OBJECTIVE The goal of this systematic review was three-pronged: (1) to determine the quality of studies using digital PA intervention strategies with preschool-aged children (ie, 3 to 5 years old); (2) to assess the efficacy of digital interventions and approaches designed to improve PA in preschool-aged children; and (3) to examine theoretical application and implementation outcomes with current approaches to digital PA interventions. METHODS This review identified and summarized studies on digitally supported interventions for promoting PA in preschool-aged children. We generated 3 lists of relevant search terms that included technology-related terms, PA-related terms, and weight-related terms. The search included Ovid MEDLINE(R) and Epub Ahead of Print, In-Process & Other Non-Indexed Citations, and Daily, Ovid EMBASE, Ovid Cochrane Central Register of Controlled Trials, Ovid Cochrane Database of Systematic Reviews, and Scopus. Study selection was led by a single author and verified by a second; the same 2 authors assessed study quality using a standardized tool, and 3 authors completed data extraction on PA outcomes, theory application, and implementation outcomes. RESULTS In total, 601 studies were identified; 8 met the inclusion criteria. For study quality, only 2 studies received an overall rating of strong quality and low risk of bias. All but 1 study had a small sample size (<100). Positive and significant changes in child PA outcomes were reported in only 2 studies with weak overall quality, both of which used child-directed approaches. In total, 5 studies applied a behavioral theory for designing the intervention; no patterns of effectiveness were identified based on the application of theory. Finally, no studies reported on the implementation outcomes of adoption, cost, penetration, or sustainability; 1 study did not assess any implementation outcomes, and no single study reported on more than 2 implementation outcomes. Studies measured the implementation outcome of acceptability most frequently (n=4), and researchers assessed fidelity in 3 studies. CONCLUSIONS The interventions with a significant effect on PA used child-centered activities; parent-directed digital interventions alone were ineffective for improving PA. Future research with rigorous designs, monitoring of implementation outcomes, and testing of the contributions of digital components will advance understanding of the effectiveness of digital interventions for increasing PA in children.
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Acute effect of high-definition and conventional tDCS on exercise performance and psychophysiological responses in endurance athletes: a randomized controlled trial.
da Silva Machado, DG, Bikson, M, Datta, A, Caparelli-Dáquer, E, Unal, G, Baptista, AF, Cyrino, ES, Li, LM, Morya, E, Moreira, A, et al
Scientific reports. 2021;11(1):13911
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Exercise-induced fatigue can be associated with a limited descending command from the central nervous system to the muscle which may affect muscle contraction and its ability to generate force. Transcranial direct current stimulation (tDCS) is the application of weak electrical current to stimulate different areas of the brain to influence exercise performance and perception. High-definition transcranial direct current stimulation (HD-tDCS) is a modification of conventional tDCS to increase the focality, precision, long-lasting effects and greater neuronal excitability change. This single-centre, randomised, crossover, single-blinded, sham-controlled trial compared the effects of HD-tDCS and conventional tDCS on exercise performance and psychophysiological responses in healthy young male endurance athletes. The study found no effect of HD-tDCS or conventional tDCS on exercise performance and psychophysiological responses to exhaustive exercise. Further robust studies are required to evaluate the effects of both forms of tDCS in athletes compared to non-athletes and its effects when tDCS is applied to other areas of the central nervous system. Healthcare professionals can use the results of this study to understand that there is no evidence currently to support the utilisation of tDCS in improving exercise performance in athletes.
Abstract
Transcranial direct current stimulation (tDCS) has been used aiming to boost exercise performance and inconsistent findings have been reported. One possible explanation is related to the limitations of the so-called "conventional" tDCS, which uses large rectangular electrodes, resulting in a diffuse electric field. A new tDCS technique called high-definition tDCS (HD-tDCS) has been recently developed. HD-tDCS uses small ring electrodes and produces improved focality and greater magnitude of its aftereffects. This study tested whether HD-tDCS would improve exercise performance to a greater extent than conventional tDCS. Twelve endurance athletes (29.4 ± 7.3 years; 60.15 ± 5.09 ml kg-1 min-1) were enrolled in this single-center, randomized, crossover, and sham-controlled trial. To test reliability, participants performed two time to exhaustion (TTE) tests (control conditions) on a cycle simulator with 80% of peak power until volitional exhaustion. Next, they randomly received HD-tDCS (2.4 mA), conventional (2.0 mA), or active sham tDCS (2.0 mA) over the motor cortex for 20-min before performing the TTE test. TTE, heart rate (HR), associative thoughts, peripheral (lower limbs), and whole-body ratings of perceived exertion (RPE) were recorded every minute. Outcome measures were reliable. There was no difference in TTE between HD-tDCS (853.1 ± 288.6 s), simulated conventional (827.8 ± 278.7 s), sham (794.3 ± 271.2 s), or control conditions (TTE1 = 751.1 ± 261.6 s or TTE2 = 770.8 ± 250.6 s) [F(1.95; 21.4) = 1.537; P = 0.24; η2p = 0.123]. There was no effect on peripheral or whole-body RPE and associative thoughts (P > 0.05). No serious adverse effect was reported. A single session of neither HD-tDCS nor conventional tDCS changed exercise performance and psychophysiological responses in athletes, suggesting that a ceiling effect may exist.
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Systematic review of the prospective association of daily step counts with risk of mortality, cardiovascular disease, and dysglycemia.
Hall, KS, Hyde, ET, Bassett, DR, Carlson, SA, Carnethon, MR, Ekelund, U, Evenson, KR, Galuska, DA, Kraus, WE, Lee, IM, et al
The international journal of behavioral nutrition and physical activity. 2020;17(1):78
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The health benefits of physical activity for people of all ages, fitness levels, and sociodemographic backgrounds are well-documented. The main aim of this study was to provide an updated description of the association between daily step counts and subsequent cardiovascular disease (CVD) morbidity or mortality, dysglycaemia, and all-cause mortality in adults and the patterns of these associations. This study is a systemic review of 17 studies from 13 different cohorts. Participants’ mean age ranged from 49.7 to 78.9 years with samples comprised of 46.9% female participants on average. Results showed that increasing steps per day is beneficial for health: taking more steps per day was associated with lower risk of all-cause mortality, and lower risk of CVD morbidity or mortality. These associations appear to hold across age, gender, and weight status. Authors conclude that this additional evidence will help guide meaningful volume targets that can be used for health care, education, and behavioural interventions, and potentially inform the development of public health guidelines for steps and health.
Abstract
BACKGROUND Daily step counts is an intuitive metric that has demonstrated success in motivating physical activity in adults and may hold potential for future public health physical activity recommendations. This review seeks to clarify the pattern of the associations between daily steps and subsequent all-cause mortality, cardiovascular disease (CVD) morbidity and mortality, and dysglycemia, as well as the number of daily steps needed for health outcomes. METHODS A systematic review was conducted to identify prospective studies assessing daily step count measured by pedometer or accelerometer and their associations with all-cause mortality, CVD morbidity or mortality, and dysglycemia (dysglycemia or diabetes incidence, insulin sensitivity, fasting glucose, HbA1c). The search was performed across the Medline, Embase, CINAHL, and the Cochrane Library databases from inception to August 1, 2019. Eligibility criteria included longitudinal design with health outcomes assessed at baseline and subsequent timepoints; defining steps per day as the exposure; reporting all-cause mortality, CVD morbidity or mortality, and/or dysglycemia outcomes; adults ≥18 years old; and non-patient populations. RESULTS Seventeen prospective studies involving over 30,000 adults were identified. Five studies reported on all-cause mortality (follow-up time 4-10 years), four on cardiovascular risk or events (6 months to 6 years), and eight on dysglycemia outcomes (3 months to 5 years). For each 1000 daily step count increase at baseline, risk reductions in all-cause mortality (6-36%) and CVD (5-21%) at follow-up were estimated across a subsample of included studies. There was no evidence of significant interaction by age, sex, health conditions or behaviors (e.g., alcohol use, smoking status, diet) among studies that tested for interactions. Studies examining dysglycemia outcomes report inconsistent findings, partially due to heterogeneity across studies of glycemia-related biomarker outcomes, analytic approaches, and sample characteristics. CONCLUSIONS Evidence from longitudinal data consistently demonstrated that walking an additional 1000 steps per day can help lower the risk of all-cause mortality, and CVD morbidity and mortality in adults, and that health benefits are present below 10,000 steps per day. However, the shape of the dose-response relation is not yet clear. Data are currently lacking to identify a specific minimum threshold of daily step counts needed to obtain overall health benefit.
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Effect of tai chi versus aerobic exercise for fibromyalgia: comparative effectiveness randomized controlled trial.
Wang, C, Schmid, CH, Fielding, RA, Harvey, WF, Reid, KF, Price, LL, Driban, JB, Kalish, R, Rones, R, McAlindon, T
BMJ (Clinical research ed.). 2018;360:k851
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Fibromyalgia is a complex disorder, characterised by chronic widespread musculoskeletal pain, fatigue, sleep problems and depression. Conventional treatment is multidisciplinary, including medication, exercise and CBT. This randomised, single-blinded trial aimed to determine the effectiveness of regular Tai Chi practice when compared to the standard recommended exercise, aerobic training. 226 adults diagnosed with fibromyalgia were randomly assigned to either 24 weeks of supervised aerobic exercise or 12 or 24 weeks of Tai Chi classes. A standard fibromyalgia impact questionnaire was used to assess changes in pain and quality of life measures, along with patient perception of various aspects of their condition. The study found that Fibromyalgia Impact Questionnaire scores improved across all treatment groups, however the 24-week Tai Chi group saw a statistically significant greater improvement than the aerobic group. In addition, those patients on the 24-week Tai Chi programme experienced greater improvement than those on the 12-week Tai Chi programme. There was also higher attendance and fewer drop-outs in the Tai Chi groups in comparison to the aerobic exercise group. Tai Chi could therefore be considered as an alternative to aerobic exercise in a multi-disciplinary approach to fibromyalgia treatment.
Abstract
OBJECTIVES To determine the effectiveness of tai chi interventions compared with aerobic exercise, a current core standard treatment in patients with fibromyalgia, and to test whether the effectiveness of tai chi depends on its dosage or duration. DESIGN Prospective, randomized, 52 week, single blind comparative effectiveness trial. SETTING Urban tertiary care academic hospital in the United States between March 2012 and September 2016. PARTICIPANTS 226 adults with fibromyalgia (as defined by the American College of Rheumatology 1990 and 2010 criteria) were included in the intention to treat analyses: 151 were assigned to one of four tai chi groups and 75 to an aerobic exercise group. INTERVENTIONS Participants were randomly assigned to either supervised aerobic exercise (24 weeks, twice weekly) or one of four classic Yang style supervised tai chi interventions (12 or 24 weeks, once or twice weekly). Participants were followed for 52 weeks. Adherence was rigorously encouraged in person and by telephone. MAIN OUTCOME MEASURES The primary outcome was change in the revised fibromyalgia impact questionnaire (FIQR) scores at 24 weeks compared with baseline. Secondary outcomes included changes of scores in patient's global assessment, anxiety, depression, self efficacy, coping strategies, physical functional performance, functional limitation, sleep, and health related quality of life. RESULTS FIQR scores improved in all five treatment groups, but the combined tai chi groups improved statistically significantly more than the aerobic exercise group in FIQR scores at 24 weeks (difference between groups=5.5 points, 95% confidence interval 0.6 to 10.4, P=0.03) and several secondary outcomes (patient's global assessment=0.9 points, 0.3 to 1.4, P=0.005; anxiety=1.2 points, 0.3 to 2.1, P=0.006; self efficacy=1.0 points, 0.5 to 1.6, P=0.0004; and coping strategies, 2.6 points, 0.8 to 4.3, P=0.005). Tai chi treatment compared with aerobic exercise administered with the same intensity and duration (24 weeks, twice weekly) had greater benefit (between group difference in FIQR scores=16.2 points, 8.7 to 23.6, P<0.001). The groups who received tai chi for 24 weeks showed greater improvements than those who received it for 12 weeks (difference in FIQR scores=9.6 points, 2.6 to 16.6, P=0.007). There was no significant increase in benefit for groups who received tai chi twice weekly compared with once weekly. Participants attended the tai chi training sessions more often than participants attended aerobic exercise. The effects of tai chi were consistent across all instructors. No serious adverse events related to the interventions were reported. CONCLUSION Tai chi mind-body treatment results in similar or greater improvement in symptoms than aerobic exercise, the current most commonly prescribed non-drug treatment, for a variety of outcomes for patients with fibromyalgia. Longer duration of tai chi showed greater improvement. This mind-body approach may be considered a therapeutic option in the multidisciplinary management of fibromyalgia. TRIAL REGISTRATION ClinicalTrials.gov NCT01420640.
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Inflammation and glucose homeostasis are associated with specific structural features among adults without knee osteoarthritis: a cross-sectional study from the osteoarthritis initiative.
Stout, AC, Barbe, MF, Eaton, CB, Amin, M, Al-Eid, F, Price, LL, Lu, B, Lo, GH, Zhang, M, Pang, J, et al
BMC musculoskeletal disorders. 2018;19(1):1
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Individuals with osteoarthritis (OA) typically present with greater systemic inflammation and impaired glucose homeostasis. Currently it is unclear whether these factors are associated with early-stage OA, namely bone marrow lesions and swelling. The purpose of this cross-sectional study was to investigate the role of inflammation and glucose homeostasis in early-stage OA. Using baseline data from the Osteoarthritis Initiative, 343 participants were enrolled and tested for markers of inflammation and impaired glucose homeostasis. Bone marrow lesions and swelling were also assessed through imaging results. Results indicate that among individuals without OA, those with greater systemic inflammation were more likely to have bone marrow lesions and knee swelling. According to these results, the authors conclude that systemic inflammation and glucose homeostasis are related to structural features of osteoarthritis. Future studies should explore whether these factors are predictive of OA in order to identify therapeutic targets to prevent or delay the onset of knee OA.
Abstract
BACKGROUND Greater age and body mass index are strong risk factors for osteoarthritis (OA). Older and overweight individuals may be more susceptible to OA because these factors alter tissue turnover in menisci, articular cartilage, and bone via altered glucose homeostasis and inflammation. Understanding the role of inflammation and glucose homeostasis on structural features of early-stage OA may help identify therapeutic targets to delay or prevent the onset of OA among subsets of adults with these features. We examined if serum concentrations of glucose homeostasis (glucose, glycated serum protein [GSP]) or inflammation (C-reactive protein [CRP]) were associated with prevalent knee bone marrow lesions (BMLs) or effusion among adults without knee OA. METHODS We conducted a cross-sectional study using baseline data from the Osteoarthritis Initiative. We selected participants who had no radiographic knee OA but were at high risk for knee OA. Blinded staff conducted assays for CRP, GSP, and glucose. Readers segmented BML volume and effusion using semi-automated programs. Our outcomes were prevalent BML (knee with a BML volume > 1 cm3) and effusion (knee with an effusion volume > 7.5 cm3). We used logistic regression models with CRP, GSP, or glucose concentrations as the predictors. We adjusted for age, sex, body mass index (BMI), and Physical Activity Scale for the Elderly (PASE) scores. RESULTS We included 343 participants: mean age = 59 ± 9 years, BMI = 27.9 ± 4.5 kg/m2, PASE score = 171 ± 82, and 64% female. Only CRP was associated with BML prevalence (odds ratio [OR] = 1.43, 95% confidence interval [CI] = 1.09 to 1.87). For effusion, we found an interaction between BMI and CRP: only among adults with a BMI <25 kg/m2 was there a significant trend towards a positive association between CRP and effusion (OR = 1.40, 95% CI = 1.00 to 1.97). We detected a U-shaped relationship between GSP and effusion prevalence. Fasting glucose levels were not significantly associated with the presence of baseline effusion or BML. CONCLUSIONS Among individuals without knee OA, CRP may be related to the presence of BMLs and effusion among normal weight individuals. Abnormal GSP may be associated with effusion. Future studies should explore whether inflammation and glucose homeostasis are predictive of symptomatic knee OA.
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Cardiovascular effects of intensive lifestyle intervention in type 2 diabetes.
Johnston, CA, Moreno, JP, Foreyt, JP
Current atherosclerosis reports. 2014;16(12):457
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Obesity is a metabolic risk factor for Type 2 diabetes (T2D) and cardiovascular diseases(CVD). This study was carried out to measure the effectiveness of lifestyle interventions on cardiovascular morbidity and mortality. 5145 overweight and obese patients with T2D were randomised assigned in groups with lifestyle interventions of weight loss through exercise and reduced calorie intake. The control group were given diabetes support and education. The data from this study suggest that lifestyle interventions were effective in weight loss and management of the CVD. However reducing the risk of CVD in comparison to the control group was not determined.
Abstract
Look AHEAD (Action for Health in Diabetes) was a randomized controlled trial that examined the impact of long-term participation in an intensive weight loss intervention on cardiovascular disease (CVD) morbidity and mortality in people with type 2 diabetes (T2D). The results from this trial suggest that intensive lifestyle interventions are effective in helping patients to achieve management of cardiovascular risk factors and reducing the need to initiate medication usage to manage these conditions, though the benefits in terms of the prevention of CVD morbidity and mortality beyond those achieved through aggressive medical management of hypertension and dyslipidemia is not clear. Additional benefits of participation in an intensive lifestyle intervention such as lowered chronic kidney disease risk, blood pressure, medication usage, improved sleep apnea, and partial remission of diabetes are discussed.
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Cardiovascular effects of intensive lifestyle intervention in type 2 diabetes.
Wing, RR, Bolin, P, Brancati, FL, Bray, GA, Clark, JM, Coday, M, Crow, RS, Curtis, JM, Egan, CM, Espeland, MA, et al
The New England journal of medicine. 2013;369(2):145-54
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Weight loss is recommended for overweight or obese patients with type 2 diabetes as it increases glycaemic control, reduces risk factors of cardiovascular disease and improves overall quality of life. These benefits, however, are based on short-term studies and the long-term effects of weight loss in this population have not been examined. The aim of this randomised trial was to elucidate whether an intensive lifestyle intervention of weight loss and increased physical activity would decrease cardiovascular morbidity and mortality in overweight or obese adults with type 2 diabetes. Participants were either assigned to an intervention group receiving diet and exercise counselling, or a control group receiving diabetes support and education. A total of 5145 patients were enrolled in the study and the median follow-up was nearly 10 years. The findings of this study showed that an intensive lifestyle intervention did not reduce the risk of cardiovascular morbidity and mortality, as compared with a control programme of diabetes support and education, among overweight and obese patients. While this primary outcome was not reduced, participants in the intervention group experienced various clinically beneficial outcomes throughout the follow-up period.
Abstract
BACKGROUND Weight loss is recommended for overweight or obese patients with type 2 diabetes on the basis of short-term studies, but long-term effects on cardiovascular disease remain unknown. We examined whether an intensive lifestyle intervention for weight loss would decrease cardiovascular morbidity and mortality among such patients. METHODS In 16 study centers in the United States, we randomly assigned 5145 overweight or obese patients with type 2 diabetes to participate in an intensive lifestyle intervention that promoted weight loss through decreased caloric intake and increased physical activity (intervention group) or to receive diabetes support and education (control group). The primary outcome was a composite of death from cardiovascular causes, nonfatal myocardial infarction, nonfatal stroke, or hospitalization for angina during a maximum follow-up of 13.5 years. RESULTS The trial was stopped early on the basis of a futility analysis when the median follow-up was 9.6 years. Weight loss was greater in the intervention group than in the control group throughout the study (8.6% vs. 0.7% at 1 year; 6.0% vs. 3.5% at study end). The intensive lifestyle intervention also produced greater reductions in glycated hemoglobin and greater initial improvements in fitness and all cardiovascular risk factors, except for low-density-lipoprotein cholesterol levels. The primary outcome occurred in 403 patients in the intervention group and in 418 in the control group (1.83 and 1.92 events per 100 person-years, respectively; hazard ratio in the intervention group, 0.95; 95% confidence interval, 0.83 to 1.09; P=0.51). CONCLUSIONS An intensive lifestyle intervention focusing on weight loss did not reduce the rate of cardiovascular events in overweight or obese adults with type 2 diabetes. (Funded by the National Institutes of Health and others; Look AHEAD ClinicalTrials.gov number, NCT00017953.).
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Three 15-min bouts of moderate postmeal walking significantly improves 24-h glycemic control in older people at risk for impaired glucose tolerance.
DiPietro, L, Gribok, A, Stevens, MS, Hamm, LF, Rumpler, W
Diabetes care. 2013;36(10):3262-8
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The insulin response is known to decline with age, which puts older people at risk of hyperglycaemia after eating. Insulin and exercise stimulate the uptake of glucose into skeletal muscle so exercise could aid insulin in age-related impaired glucose tolerance (IGT). This small randomised controlled trial (RCT) used a multiple crossover design to compare the effect of exercise timing and frequency on glycaemia control in older people. The ten trial subjects were at risk of impaired glucose tolerance (IGT), but were otherwise healthy with an average age of sixty-nine years old. Subjects were housed in whole room calorimeters, fed three standardised meals a day and glucose levels were monitored. Subjects were randomly assigned to walk on a treadmill for either fifteen minutes after each of the three meals, or walk for forty-five minutes either at mid-morning or mid-afternoon. It was found that that both the morning walk and the post-meal walking decreased 24 hour glucose concentration, whilst the afternoon walk had little impact. Post-meal walking was effective at lowering glucose levels after each meal including dinner, where the other exercise protocols were not. The author concluded that the timing of the exercise may be as important, if not more, than volume. Short (15 minute) bouts of post-meal walking could be manageable for older people and appears to be an effective way of controlling post eating hyperglycaemia.
Abstract
OBJECTIVE The purpose of this study was to compare the effectiveness of three 15-min bouts of postmeal walking with 45 min of sustained walking on 24-h glycemic control in older persons at risk for glucose intolerance. RESEARCH DESIGN AND METHODS Inactive older (≥60 years of age) participants (N=10) were recruited from the community and were nonsmoking, with a BMI<35 kg/m2 and a fasting blood glucose concentration between 105 and 125 mg dL(-1). Participants completed three randomly ordered exercise protocols spaced 4 weeks apart. Each protocol comprised a 48-h stay in a whole-room calorimeter, with the first day serving as the control day. On the second day, participants engaged in either 1) postmeal walking for 15 min or 45 min of sustained walking performed at 2) 10:30 a.m. or 3) 4:30 p.m. All walking was on a treadmill at an absolute intensity of 3 METs. Interstitial glucose concentrations were determined over 48 h with a continuous glucose monitor. Substrate utilization was measured continuously by respiratory exchange (VCO2/VO2). RESULTS Both sustained morning walking (127±23 vs. 118±14 mg dL(-1)) and postmeal walking (129±24 vs. 116±13 mg dL(-1)) significantly improved 24-h glycemic control relative to the control day (P<0.05). Moreover, postmeal walking was significantly (P<0.01) more effective than 45 min of sustained morning or afternoon walking in lowering 3-h postdinner glucose between the control and experimental day. CONCLUSIONS Short, intermittent bouts of postmeal walking appear to be an effective way to control postprandial hyperglycemia in older people.
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Physiologic and behavioral indicators of energy deficiency in female adolescent runners with elevated bone turnover.
Barrack, MT, Van Loan, MD, Rauh, MJ, Nichols, JF
The American journal of clinical nutrition. 2010;92(3):652-9
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Young female runners are more likely to have a low bone mass for their age. It is thought that this might be partly due to them using more energy (calories) than they consume. This study looked at the relationship between nutrition intake and biomarkers of bone turnover in young female runners. Participants were competitive cross-country runners, aged 14-17. The girls ate their usual diet and kept a food diary for a week, to allow the researchers to analyse their nutritional intakes. Runners that had an elevated bone turnover consumed significantly less calories and calcium than the runners with a normal bone turnover. They were also more likely to have a lower body mass, fewer menstrual cycles, lower oestrogen and vitamin D levels, lower BMI and lower bone mass. The authors concluded that nutritional support to increase energy and calcium intake, and vitamin D levels may improve bone growth in young female runners.
Abstract
BACKGROUND Female adolescent runners have an elevated prevalence of low bone mass for agemdashan outcome that may be partially due to inadequate energy intake. OBJECTIVE The objective was to evaluate diet, menstrual history, serum hormone concentrations, and bone mass in female adolescent runners with normal or abnormal bone turnover. DESIGN Thirty-nine cross-country runners (age: 15.7 plusmn 0.2 y) participated in the study, which included a 7-d dietary assessment with the use of a food record and daily 24-h dietary recalls; serum measures of insulin-like growth factor I, estradiol, leptin, parathyroid hormone, progesterone, triiodothyronine, 25-hydroxycholecalciferol, bone-specific alkaline phosphatase (BAP), and cross-linked C-telopeptides of type I collagen (CTX); an evaluation of height, weight, bone mass, and body composition with the use of dual-energy X-ray absorptiometry; and a questionnaire to assess menses and sports participation. Age- and sex-specific BAP and CTX concentrations of at least the 97th percentile and no greater than the third percentile, respectively, were considered abnormal. RESULTS All abnormal BAP and CTX concentrations fell within the elevated ( ge 97%) range. Runners with an elevated bone turnover (EBT) (n = 13) had a lower body mass, fewer menstrual cycles in the past year, lower estradiol and 25-hydroxycholecalciferol concentrations, and a higher prevalence of body mass index lt 10% for age, vitamin D insufficiency, amenorrhea, and low bone mass. Girls with EBT consumed less than the recommended amounts of energy and had a higher prevalence of consuming lt 1300 mg Ca than did those with normal bone turnover. CONCLUSIONS Runners with EBT had a profile consistent with energy deficiency. Nutritional support to increase energy, calcium intake, and 25-hydroxycholecalciferol concentrations may improve bone mineral accrual in young runners with EBT. This trial was registered at clinicaltrials.gov as NCT01059968.
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Estrogen and progesterone exposure is reduced in response to energy deficiency in women aged 25-40 years.
Williams, NI, Reed, JL, Leidy, HJ, Legro, RS, De Souza, MJ
Human reproduction (Oxford, England). 2010;25(9):2328-39
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Diet and exercise are related to a reduction in breast cancer risk, and it is thought that this is at least partly due to their impact on levels of female sex hormones. This study aimed to test the effect that exercise and calorie restriction have on menstruation and sex hormones in premenopausal women. Inactive women aged 25-40 years were recruited for the study, and allocated to two groups. One group was assigned a low-calorie diet that provided 20-35% lower calories than baseline energy needs, plus 4 sessions of moderate-intensity exercise per week. The control group followed a diet designed to ensure weight maintenance, and took part in shorter exercise sessions twice a week. Women in the low-calorie group experienced a 15% reduction in levels of oestradiol and a 20% reduction in the levels of oestrogen metabolite oestrone glucuronide. Larger reductions in oestrone glucuronide were related to higher energy deficits, suggesting that hormone production is sensitive to day-to-day fluctuations in energy balance. There was no change in the menstrual cycles of the participants. The researchers concluded that an energy deficit is a more important factor in reducing oestrogen exposure than losing weight.
Abstract
BACKGROUND Alterations in circulating steroids are believed to be important mediators of the impact that diet and exercise have on breast cancer risk and changes in bone density. This study aimed to test the hypothesis that moderate exercise training combined with caloric restriction would produce significant menstrual disturbances and alterations in ovarian steroids in premenopausal women. METHODS Sedentary premenopausal women (25-40 years; body mass index: 23.6 +/- 0.6 kg/m(2)) assigned to either a light conditioning (LC, n = 9) or an exercise combined with caloric restriction group (EX + CR, n = 24) were studied for one screening, one baseline and four intervention periods equivalent to the length of subjects' menstrual cycles. Exercise consisted of supervised training sessions, i.e. two LC or four EX + CR times per week, 30-60 min at a moderate intensity. The EX + CR group was prescribed a diet representing a caloric restriction of 20-35% below baseline energy requirements, whereas the LC group remained eucaloric. Ovarian steroid exposure was determined with daily urinary estrone-1- and pregnanediol glucuronides (E1G and PdG, respectively) and mid-cycle urinary LH measures. Fitness, body composition, and serum sex hormone binding globulin (SHBG) and serum estradiol (E2) were assessed repeatedly. RESULTS The intervention produced significant increases in VO(2) max and decreases in both body weight (-3.7 +/- 0.5 kg; ranged from -8.8 to +1.8 kg) and percent body fat (-4.5 +/- 0.7%; ranged from -12 to +0.3%), which were attributable primarily to changes in the EX + CR subjects (time x group; P < 0.05). Serum E2 and urinary E1G and PdG concentrations declined significantly across the intervention period (time; P < 0.05), whereas SHBG increased transiently (time; P < 0.05) in the EX + CR subjects, with no significant changes observed in the LC group. The decrease in E1G area under the curve was significantly related to the daily energy deficit (R =0.61; P = 0.003), not the amount of weight lost. There was no significant impact of the intervention on menstrual cyclicity or the incidence of menstrual disturbances in either group. CONCLUSIONS A moderate aerobic exercise training program combined with modest weight loss in accordance with recommended guidelines produces significant reductions in ovarian steroid exposure without disrupting menstrual cyclicity in premenopausal women aged 25-40 years. Exposure to a daily energy deficit is a stronger predictor of the decline in estrogen exposure than decreases in body weight.